Formation And Scavenging Characteristics Of Biofilm In Cold Meat

As the main and increasing market share of meat sales method,the humid and nutritious surface of cold meat production and processing chain provides the environment for the breed of bacteria and formation of biofilm.Compared to the bacteria without biofilm-forming ability,the bacteria with such ability can more hardly adhere to the surface of stainless steel and equipment or appliance of glass material,and cannot be cleared up easily so as to cause potential safety hazard of food contamination.This study mainly research on the features of biofilm of mixed bacteria in cold meat available in the market,take leacheate of it as the culture medium,to explore the formational situation of the bacteria’s bioflim under different materials,temperatures and incubation time,and separate the strains with single film-forming ability from the matured bacteria,and take 16 s RNA sequencing comparison method to identify its species.By using combination of sodium hypochlorite and ultrasonic wave to clear up bacteria biofilm,and simulating the low temperature condition of processing cold meat to clear up its biofilm,it has gained great effect.The followings are the main research results:(1)To collect from the supermarket freezer,the total number of bacteria on the determination results of cold meat was 2.6 x105cfu/g,lower than the national standard.For cold meat leacheate cultivation matrix,the original as experimental object,the mixed bacteria biofilm formation.Incubation time has significant influence on the formation of biofilms,under 4℃,the generation of biofilm increased 6 days to peak,significantly higher than other time.The formation of biofilm was no significant difference in the mixed bacteria liquid interface type glass and stainless steel surface.Temperature has significant influence on the formation of biofilms,6 days under 4℃ gained the optimal amount of biofilm formation and had no significant difference with 26℃,but significantly higher than 15℃ under the condition of biofilm formation.(2)To separated strains from the mature biofilm bacteria.From more than 200 suspected bacterial strains with single film-forming ability,screened 9 strains of bacteria with strong film-forming ability,itsspecific biofilm formation(SBF)all greater than 1.Sequence analysis of 16 S RNA was used for the identification of 9 bacteria strains.According to the results,one of the strains was Pseudomonas caeni,one was Pantoea agglomerans,two wereProteus vulgaris and five strains were Shewanella putrefaciens.(3)Chemical detergent sodium hypochlorite solution,and ultrasonic removal treatment had significantly inactivated effecton the inner wall of the glass tube of biofilm formation,the removal effect is obvious.Only Ultrasound treated on the surface of glass and stainless steel surface,biofilm removal efficiency is 60% and 50% respectively.Sodium hypochlorite solution of biofilm removal was more than 90%,and the concentration of 200 ppm,400 ppm,the clearance rate had no significant difference between 600 ppm.A separate removal effect of sodium hypochlorite solutionis was significantly better than ultrasonic removal effect.For different material of glass and stainless steel pieces,two kinds of material removal effect of each treatment had no significant difference.